The long term goal of our research is to define the tissue and developmental-specific regulation of the globin genes and to eventually understand erythroid cell development. An understanding of the cellular and molecular basis of the regulated expression of adult beta hemoglobin is important for two reasons. First, it will provide detailed knowledge of how genes are controlled during development and regulated in general, and second and equally important, it should provide the basis for exploring new approaches to the treatment of certain hemoglobinopathies. Clearly this would be helpful in sickle cell anemia, where an understanding at the molecular level of the mechanisms governing the switch from fetal to adult hemoglobin could present new avenues for preventing or reversing this switch. In keeping with this goal, the specific aims of our studies are as follows: 1. Characterization of a newly identified cis element in the distal 5' flanking sequence of the human beta globin gene. Our recent studies have identified a new cis element involved in the expression of the human globin gene and we are now characterizing this element and the transacting factors which interact with it. This element is particularly noteworthy as it may form a link between the beta globin gene and its locus activating region, i.e. HS2. Both deletion and site-directed mutagenesis will be used along with footprinting and oligonucleotide competition studies to localize the nucleotide binding site. Efforts to purify the factor(s) binding to this site will include the use of the yeast one-hybrid system as well as conventional approaches. 2. Regulation of the EKLF gene. We have also initiated studies on the regulation of the EKLF gene which codes for a transcription factor required for beta globin gene expression and has been implicated as one of the key elements necessary for the fetal-to-adult switch in globin gene expression. We plan to define the cis elements and transacting factors responsible for the tissue specific expression of the EKLF gene. Together, these studies will provide new insights into mechanisms of erythroid-specific gene regulation and the biology of hematopoietic systems.